Well ideally it would be decentralized, thats what Satoshi intended with Bitcoin, decentralization.
As far as Bitifinex goes, I used to wonder about their legitimacy, but their volume is pretty high, so they are making good money from commissions, and it is in their better interest to continue running the exchange well than to abscond with depositors' funds. Not sure about legal recourse if they failed, but Hong Kong has a well-deserved reputation for fair business practices. Note: Bitfinex is definitely in Hong Kong because the SWIFT number used in routing is location-specific.

I dont know about the inside information thing tho.